House Republican leaders are quietly hatching a plan of attack as they await a historic Supreme Court ruling on President Barack Obama’s health care law.

If the law is upheld, Republicans will take to the floor to tear out its most controversial pieces, such as the individual mandate and requirements that employers provide insurance or face fines.

If the law is partially or fully overturned they’ll draw up bills to keep the popular, consumer-friendly portions in place — like allowing adult children to remain on parents’ health care plans until age 26, and forcing insurance companies to provide coverage for people with pre-existing conditions. Ripping these provisions from law is too politically risky, Republicans say.

The post-Supreme Court plan — a ruling should come in June — has long been whispered about inside House leadership circles and among the House’s elected physicians but is now being discussed with a larger groups of lawmakers, showing that Republicans are aggressively preparing for a big-time health care debate in the heat of an election-year summer.

On Tuesday, the major options were discussed during a small closed meeting of House Republican leaders, according to several sources present.

Then on Wednesday, Speaker John Boehner (R-Ohio) gave the entire House Republican Conference a preview of where the party is heading. His message: “When the court rules, we’ll be ready.”

But Boehner warned that they’ll relegislate the issue in smaller, bite sizes, rather than putting together an unwieldy new health care bill.

“If all or part of the law is struck down, we are not going to repeat the Democrats’ mistakes,” Boehner said, according to several sources present. “We have better ideas on health care — lots of them. We have solutions, of course, for patients with pre-existing conditions and other challenges.”

The plan represents an aggressive posture from House Republicans. It seeks to shelter them from criticism from the left that they’re leaving uninsured Americans out to dry. Aides caution the plans could still be changed — but this outline, confirmed by several sources with direct knowledge of the planning, represents the broad sketch of what’s likely to come this summer.

The court is expected to issue its ruling on the mandate and the future of the health law in late June. The ruling is all but sure to be the most controversial of the term, sending health care back into the headlines and making it a major talking point on the campaign trail.

Opening the legislative can of worms on health care after such an emotional Supreme Court ruling would be tricky — and would come with major risks.

First, if the law’s popular insurance provisions are struck, Republicans know Democrats are going to blame them for “putting insurance companies back in charge” — a refrain Obama has already used on the campaign trail.

That’s why Republicans would try to replace some of the consumer-friendly parts of the plan — they don’t want it to seem like they’re leaving millions of Americans out to dry. They’ll look to protect some of the law’s most popular provisions, such as allowing people to stay on their parents’ insurance until 26 and forcing insurance companies to provide coverage to those with pre-existing conditions. They also want to keep the Medicare “donut hole” closed — essentially they don’t want seniors paying sky-high costs for prescription drugs.

Pushing these small bills helps them avoid the “angst of the electorate that ‘you followed Obamacare with some other bill no one has read,’” said Rep. Phil Gingrey (R-Ga.), one of the House’s elected physicians.

But even with those insurance industry reforms — which poll well with the public — Republicans could run into resistance from conservatives, who want to repeal the entire health care law and leave nothing in its place.

“I don’t want any vestige of Obamacare left in law,” Rep. Steve King (R-Iowa) said. “Not one particle of DNA.”

Before they even put together a bunch of piecemeal health care bills, Republicans would have to overcome their own differences.

For example, Georgia Rep. Tom Price’s health care legislation — perhaps the most comprehensive plan — does not require insurance companies to accept everyone regardless of their expensive medical conditions. But that provision is one of the health reform law’s most popular pieces — and has been embraced by a broad swath of other Republicans.

The other challenge for Republicans is purely political — they’d have to coordinate their health care message with Mitt Romney, the party’s presidential nominee, and want to avoid an intraparty brawl over health care as the party heads into its summer convention.

So far, Romney’s health plans have tracked closely with what House Republicans have pursued. The former Massachusetts governor’s Medicare reform plans is similar to the latest Medicare plan proposed by House Budget Committee Chairman Paul Ryan (R-Wis.).

Republicans also don’t want to spend too much time on health care fixes in the post Supreme Court world, since they want to stay focused on the economy. At the end of the year, income tax rates expire, as does the estate tax, the patch to the alternative minimum tax, payroll tax holiday and government funding. The rate at which the government reimburses doctors who serve Medicare patients also expires. Harsh across-the-board spending cuts are set to take place next year. Boehner said he wants to get working on this as soon as possible.

Of course, Democrats are skeptical that Republicans are serious about ensuring Americans have access to affordable health care.

“If they have something new, I look forward to seeing it, but it’s a little late,” said Rep. Henry Waxman (D-Calif.), one of the authors of the Democrats’ health law.

Republicans may not wait until the Supreme Court hands down its decision to continue movement on repeal measures. The next items to hit the floor are likely to be repeals of the health law’s medical device tax and its ban on allowing consumers to use health savings accounts to buy over-the-counter drugs. It’s a move meant to further denigrate the law and put a squeeze on Democrats in states with big manufacturers — such as Massachusetts and Minnesota.